High frequency polarization aerosol generator

ABSTRACT

A vaporizing device such as an electronic cigarette includes a housing (11) containing a battery (12) or other electrical power source electrically connected to a high frequency oscillation circuit (50). Two electrodes or electrode pads (56) with a liquid space (70) between them are electrically connected to the high frequency oscillation circuit (50). A liquid supply (34) in the C housing (11) provides a liquid into the liquid space (70). The high frequency oscillation circuit (50) is switched on by a manual switch or by a sensor (24) sensing inhalation by a user. The liquid is vaporized by dielectric heating.

TECHNICAL FIELD

The present invention relates generally to electronic smoking devices,electronic cigarettes, and similar vaporizing devices and methods.

BACKGROUND

An electronic smoking device, such as an electronic cigarette(e-cigarette), typically has a housing accommodating an electric powersource (e.g. a single use or rechargeable battery, electrical plug, orother power source), and an electrically operable atomizer. The atomizervaporizes liquid supplied from a reservoir and converts liquid into avapor or aerosol. Control electronics control the activation of theatomizer. In some devices, an airflow sensor is provided to detect auser puffing on the device (e.g., by sensing an under-pressure or an airflow pattern through the device). The airflow sensor signals the puff tothe control electronics to power up the device and generate vapor. Inother devices, a switch is used to switch on the electrically operableatomizer. These types of devices are collectively referred to here ase-cigarettes, although they may be sized and shaped unlike aconventional tobacco cigarette.

The electrically operable atomizers often use a resistance heater toheat the liquid. Resistance heaters in the form of a wire coil have beenwidely used in many e-cigarette designs. Ceramic plate heaters and solidheater rods have also been proposed. While these and others have beensuccessfully used in the past, they also present performanceconsiderations including, depending on the specific design, corrosion orbuild-up of residue on the heating element, short and long term changesin electrical resistance, and other factors which may affect thegeneration of vapor. Accordingly, engineering challenges remain in thedesign of e-cigarettes and specifically in the design of atomizers asused in e-cigarettes.

SUMMARY

In one aspect of the present invention, a vaporizing device includes ahousing containing an electrical power source such as a batteryelectrically connected to a high frequency oscillation circuit. Firstand second conductors are electrically connected to the high frequencyoscillation circuit, with a liquid space between the first and secondconductors. A liquid supply in the housing is positioned to provide aliquid into the liquid space. A switch is electrically connected to thehigh frequency oscillation circuit for turning on the high frequencyoscillation circuit to vaporize the liquid via dielectric heating. Theswitch may be provided as an inhalation sensor connected to anelectronic controller. The liquid space may be planar or annular, anddimensioned to allow liquid to flow into the liquid space via capillaryforces.

In a method of use, a polar liquid is supplied to a space between firstand second conductors connected to an oscillating high frequency source.Molecules of the polar liquid are vibrated at high frequency via theoscillating electric field created between the first and secondconductors. The vibration generates heat within the liquid causing theliquid to change into vapor. The polar liquid may include nicotine orother physiologically active substance, which is contained in the vaporand inhaled by a user.

The characteristics, features and advantages of this invention and themanner in which they are obtained will become more apparent and be moreclearly understood in connection with the following description ofexemplary embodiments, which are explained with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, the same element number indicates the same element ineach of the views.

FIG. 1 is a schematic cross-sectional illustration of an exemplarye-cigarette.

FIG. 2 is a schematic of inductance coupling oscillation voltage boostcircuit

FIG. 3 is a schematic of capacitor oscillation circuit.

FIG. 4 is a schematic of transformer oscillation circuit.

FIG. 5 is a schematic of push-pull type oscillation circuit.

FIG. 6 is a schematic of MOSFET push-pull type oscillation circuit.

FIG. 7 is a section view of electrode pads of the atomizer shown in FIG.1 .

FIG. 8 is a section view of electrode pads with a liquid conductor orwick.

FIG. 9 is a top view of a mesh electrode pad.

FIG. 10 is a section view of tube type electrode pad.

FIG. 11 is a diagram of voltage boost before the oscillation circuit.

FIG. 12 is a diagram of voltage boost after the oscillation circuit.

DETAILED DESCRIPTION

As is shown in FIG. 1 , an e-cigarette 10 typically has a housing 11having a cylindrical hollow tube which may be single piece or a multiplepiece tube. In FIG. 1 , the cylindrical hollow tube is shown as a twopiece structure having a battery section 12 and an atomizer/liquidreservoir section 14. Together the battery section 12 and theatomizer/liquid reservoir section 14 form a device which isapproximately the same size and shape as a conventional cigarette,typically about 100 mm with a 7.5 mm diameter, although lengths mayrange from 70 to 150 or 180 mm, and diameters from 5 to 20 mm.

The battery section 12 and the atomizer/liquid reservoir section 14 aretypically made of metal or plastic and act together with end capsprovide a housing to contain the operative elements of the e-cigarette10. The battery section 12 and a atomizer/liquid reservoir section 14may be configured to fit together by a friction push fit, a snap fit, ora bayonet attachment, magnetic fit, or screw threads. An end cap 16 isprovided at the front end of the battery section 12. The end cap 16 maybe translucent to allow an LED 20 positioned near the end cap to emitlight through the end cap. Alternatively the end cap may be opaque andthe LED omitted.

An air inlet 38 may be provided in the end cap, at the edge of the inletnext to the cylindrical hollow tube, anywhere along the length of thecylindrical hollow tube, or at the connection of the battery section 12and the atomizer/liquid reservoir section 14. FIG. 1 shows a pair of airinlets 38 provided at the intersection between the battery section 12and the atomizer/liquid reservoir section 14. An air outlet 40 isprovided at the back end of the atomizer/liquid reservoir section 14remote from the end cap 16. The air outlet 40 may be formed in theatomizer/liquid reservoir section 14 or it may be formed in a separateend cap or mouthpiece.

A battery 18, the LED 20, control electronics 22 and optionally anairflow sensor 24 are provided within the battery section 12. Thebattery 18 is electrically connected to the control electronics 22,which is electrically connected to the LED 20 and the airflow sensor 24.In this example the LED 20 is at the front end of the battery section12, adjacent to the end cap 16 and the control electronics 22 andairflow sensor 24 are provided in the central cavity at the other end ofthe battery 18 adjacent the atomizer/liquid reservoir section 14. Thecontrol electronics 22 may include a programmable microprocessor.

The airflow sensor 24 acts as a puff detector, detecting a user inhalingor sucking on the outlet 40. The airflow sensor 24 can be any suitablesensor for detecting changes in airflow or air pressure such amicrophone switch including a deformable membrane which is caused tomove by variations in air pressure. Alternatively the sensor may be aHall element or an electro-mechanical sensor.

The control electronics 22 are also connected to an atomizer 26 providedin the atomizer/liquid reservoir section 14. A central passage 32 may besurrounded by a cylindrical liquid supply 34 with a supply tube or wick30 abutting or extending into the liquid supply 34. The wick 30 may be aporous material such as a bundle of fiberglass fibers, with liquid 36 inthe liquid supply 34 drawn by capillary action through the wick to theatomizer 26.

The liquid supply 34 may be a flex wall or rigid wall bottle orcontainer holding bulk liquid or alternatively it may include waddingsoaked in liquid which encircles the central passage 32 with the ends ofthe wick 30 abutting the wadding. The liquid supply 34 may optionally beprovided as a toroidal cavity arranged to be filled with liquid and withthe ends of the wick 30 extending into the toroidal cavity.

Where the liquid is polar, or is otherwise subject to dielectricheating, the atomizer 26 may operate by vibrating the molecules ofliquid via a high frequency electric field (AC). This vibrationgenerates heat in the liquid, changing the liquid into vapor. The heatis generated inside the liquid. Consequently, there is no transferringof heat from a heating element, such as a resistance coil, into theliquid. Overheating and degradation are avoided. The liquid may includepropylene glycol, glycerol or glycerin, and have a dipole moment of 1.0to 8.0 Debyes.

The atomizer 26 may be provided as first and second electrodes orelectrode pads or plates 56 electrically connected to a high frequencyoscillation circuit 50, with a liquid space 70 between the pads 56. Theelectrode pads 56 are electrically conducting, and may be metal, with orwithout a non-conducting protective film or layer. The electrode pads 56can have various shapes, such as flat and round, triangular, square,tooth-like or rectangular. The dimension DD of the open space betweenthe electrode pads 56 forming the liquid space 70 may be selected sothat liquid is drawn into the liquid space 70 via capillary action. Thisdimension DD will vary depending on the characteristics of the liquidand may typically range from 0.5 to 4 mm. Where flat electrode pads 56are used, they are generally aligned and parallel to each other.

FIG. 9 shows a wire or metal mesh electrode pad 90 which may be used inplace of solid pads. FIG. 10 shows a tubular atomizer 96 having atubular or cylindrical heat insulation layer 98, a metal conductor orother conductive layer 100, and porous material or fiber layer 102.

FIG. 2 shows a high frequency oscillation circuit 50, in this caseprovided as an inductance coupling oscillation circuit 52. An inductor54 and electrode pads 56 form an LC basic oscillation loop. A capacitor58 provides a positive feedback signal and a transistor 60 forms theoscillation circuit. Liquid 36 between the electrode pads 56 undergoesdielectric heating to create a vapor.

The vapor is entrained air flow through the housing 11 and cools andcondenses to form an aerosol. FIG. 3 shows a capacitor isolation circuit124 with a transformer 112 isolated via capacitors 58, FIG. 6 shows aMOSFET push-pull type oscillation circuit 122 which may also be used.

Referring to FIG. 7 , a thermal insulator or insulation layer 72 may beprovided on the back and/or the sides of the electrode pads 56. Theinsulation layer 72 may be an open space or gap filled with air and/oraerosol, porous material, or fiber material. The electrode pad materialpreferably combines both heat insulation and electrical conductivity.Carbon aerogel may be used as the electrode pad material.

Turning to FIG. 8 , a liquid conductor 80 may be used to provide acontinuous supply of liquid to the atomizer 26. The liquid conductor 80may be a porous material extending between the two electrode pads 56.

The nominal voltage of the battery 18 (typically 1-12 V DC) may beincreased using various techniques. FIG. 11 shows an inverter 110inverting the low battery DC voltage via an inverter to a high voltageand then oscillating to provide a high frequency oscillation voltage tothe atomizer 26. FIG. 12 shows a design with the oscillation circuit 50generating a high frequency AC voltage output with a transformer 112increasing the AC voltage which is then applied to the electrode pads56. Alternatively, an inverter 110 may be used to increase the DCvoltage to drive the oscillation circuit 50, with a transformer 112 usedto increase the AC voltage applied to electrode pads 56.

High frequency voltage can be generated from a transformer isolationcircuit 118 as shown in FIG. 4 , a push-pull oscillator 120, as shown inFIG. 5 , or via a MOSFET push-pull oscillation circuit 122 as shown inFIG. 6 , with the oscillator output connected to the electrode pads 56.The high frequency oscillation circuit may operate at 50 KHz to 980 MHzand at 30 volts to 5000 volts. Different liquid compositions willvaporize efficiently using frequency and voltage combinations withinthese ranges.

In use, a user inhales on the outlet 40 causing air to be drawn into thehousing 11 via the air inlet 38 and through the central passage 32. Theresulting change in air pressure is detected by the airflow sensor 24(if used) which generates an electrical signal that is passed to thecontrol electronics 22. In response to the signal, the controlelectronics 22 activates the atomizer 26 which causes liquid 36 in theliquid space 70 to be vaporized via dielectric heating creating anaerosol (which may include gaseous and liquid components) within thecentral passage 32. Where the liquid has polar molecules, such as wateror glycol, or if the liquid has weakly bonded molecules, the moleculestend to orient into alignment with oscillating electric field, causingmolecular dipole rotation, which can quickly heat the liquid viadielectric heating.

As the user continues to inhale, the vapor is drawn through the centralpassage 32 and inhaled by the user. At the same time the controlelectronics 22 may activate the LED 20 (if used) causing the LED 20 tolight up and create light which is visible via the translucent end cap16 simulating the appearance of a glowing ember at the end of aconventional cigarette. As liquid present in the wick 30 is convertedinto an aerosol more liquid is drawn into the wick 30 from the liquidsupply 34 by capillary action and moved to the atomizer 26.

Some e-cigarette are intended to be disposable and the electric power ofthe battery 18 is intended to be sufficient to vaporize the liquidcontained within the liquid supply 34 after which the e-cigarette 10 isthrown away. In other embodiments the battery 18 is rechargeable and theliquid supply is refillable. In the cases where the liquid supply 34 isa toroidal cavity, this may be achieved by refilling the liquid supplyvia a refill port. The atomizer/liquid reservoir section 14 may bedetachable from the battery section 12 and a new atomizer/liquidreservoir section 14 can be fitted with a new liquid supply 34 therebyreplenishing the supply of liquid. In some cases, replacing the liquidsupply 34 may involve replacement of the atomizer 26 and the wick 30along with the replacement of the liquid supply 34.

The new liquid supply 34 may be in the form of a cartridge, optionallyhaving the central passage 32 through which a user inhales aerosol.Rather than inhaling aerosol via a central passage 32, the cartridge mayblock the central section of the e-cigarette 10 and generated aerosolmay be directed around the exterior of the cartridge to the outlet 40for inhalation.

Of course, in addition to the above description of the structure andfunction of a typical e-cigarette 10, variations also exist. Forexample, the LED 20 may be omitted. The airflow sensor 24 may be placedadjacent the end cap 16 rather than in the middle of the e-cigarette.The airflow sensor 24 may be replaced with a switch which enables a userto activate the e-cigarette manually rather than in response to thedetection of a change in air flow or air pressure.

Thus, novel designs have been shown and described. Various changes andsubstitutions may of course be made without departing from the spiritand scope of the invention. The invention, therefore, should not belimited, except by the following claims and their equivalents.

1. A high frequency polarization aerosol generator, comprising: ahousing containing an electrical power source electrically connected toa high frequency oscillation circuit operating at a frequency of 50 KHzto 980 MHz and at a voltage of 30 to 5000 V; the high frequencyoscillation circuit comprising an inductance coupling oscillationvoltage boost circuit including an inductor; first and second electrodepads electrically connected to the high frequency oscillation circuit,the first and second electrode pads and the inductor forming an LCoscillation loop; a space for liquid between the first and secondelectrode pads; a liquid supply in the housing positioned to provide apolar liquid into the space for liquid; and a switch electricallyconnected to the high frequency oscillation circuit for turning on thehigh frequency oscillation circuit to vaporize the liquid in the spacefor liquid via dielectric heating.
 2. The high frequency polarizationaerosol generator of claim 1 wherein the high frequency oscillationcircuit includes a capacitor for providing a positive feedback signal.3. The high frequency polarization aerosol generator of claim 1 whereinthe electrical power source comprises a battery, further comprising aninverter adapted for inverting the battery DC voltage to drive theoscillation circuit with a transformer used to increase AC voltageapplied to the electrode pads.
 4. A high frequency polarization aerosolgenerator, comprising: a housing containing an electrical power sourceelectrically connected to a high frequency oscillation circuit operatingat a frequency of 50 KHz to 980 MHz; the high frequency oscillationcircuit comprising a transformer isolation circuit; first and secondelectrode pads electrically connected to the high frequency oscillationcircuit, the first and second electrode pads and an inductor forming anLC oscillation loop; a liquid space between the first and secondelectrode pads filled with a polar liquid; and a switch electricallyconnected to the high frequency oscillation circuit for turning on thehigh frequency oscillation circuit to vaporize the liquid in the liquidspace.
 5. The high frequency polarization aerosol generator of claim 4wherein the high frequency oscillation circuit includes a capacitor forproviding a positive feedback signal.
 6. The high frequency polarizationaerosol generator of claim 1 wherein the electrical power sourcecomprises a battery, further including an inverter adapted for invertingthe battery DC voltage to drive the high frequency oscillation circuit.7. A high frequency polarization aerosol generator, comprising: ahousing containing an electrical power source electrically connected toa high frequency oscillation circuit operating at a frequency of 50 KHzto 980 MHz; the high frequency oscillation circuit comprising a MOSFETpush-pull oscillation circuit; first and second electrode padselectrically connected to the MOSFET push-pull oscillation circuit, thefirst and second electrode pads and an inductor forming an LCoscillation loop; a liquid space between the first and second electrodepads filled with a polar liquid; and a switch electrically connected tothe high frequency oscillation circuit for turning on the high frequencyoscillation circuit to vaporize the liquid in the liquid space.